I Found the safest way to clone pokemon first what you need:GAMECUBE OR TWO GBA SYTEMS and a ds with game genie backup save feature(note ds lite or original ds needed). POKEMON COLOSEUM OR OTHER POKEMON GAMES THAT ARE COMPATIBLE. steps 1.put pokemon game and gamegenie in the ds and backup the save. 2. if using gamecube turn it on with pokemon coloseum and go to pheneac city(the pokemon center with a basement)note pokemon coloseum must be beat for this to work and the gba game must be saved at a pokemon center.3. the pokemon that you are trading on to the gba will be erased so make sure its a pokemon you don't want and proceed with the trade 4.after trading put the pokemon game back in the ds and play the gamegenie and restore your save. play your gba pokemon game and realize you dont have that the gamecube gave you, you have the pokemon that you had before the trade.
the steps are similar with 2 gba's just replace the gamcube with gba tested and works. HAPPY CLONIN